Chengdu Ebyte Electronic Technology Co., Ltd.
NB144S User Manual
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Chengdu Ebyte Electronic Technology Co., Ltd.
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server address: ProductKey . iot-as-mqtt.cn-shanghai.aliyuncs.com:1883
pic for subscription and publishing : /a1GlhuTU1yN/DEV04/user/1234
Cloud MQTT platform communication test:
4.5 Channel port
random port:
TCP client, UDP client, HTTP client, MQTT client can configure the local port as 0 (use random local port),
server mode cannot use random port, otherwise the client cannot establish the connection correctly (device is not
correctly configured) port listening).
Using a random port connection can quickly re-establish the connection when the device is accidentally
disconnected from the server, preventing the server from rejecting the connection due to four waved incomplete. It
is recommended to use a random port in client mode.
When the device configures the TCP client, HTTP client, and MQTT client mode at AT , it will automatically
configure a random port, which can be canceled by customization.
Static port:
Device fixed port (factory default: 8 001-800 4 ), TCP server mode device listens to the configuration port,
accepts the connection request from the client and establishes a connection for data communication, and TCP client
mode device fixed port initiates a connection request.
